• If you like antique engines, vintage tractors or old iron, please register and join us. When registering, please provide your CITY and STATE in your location!

Briggs & Stratton model 23 spark advance

54hawken

Registered
Concerning cam gear, spring and weight. need someone to explain in detail how it works. What the weight activates etc.
 

Andrew Mackey

Moderator
Last Subscription Date
05/14/2017
There is no spark advance on the 23. The weight works to slightly open the exhaust valve on the compression stroke, making it easier to start the engine. As speed increases, the valve de-compression lift decreases, giving full action of the exhaust valve. If the return spring breaks or is missing, valve action will be erratic.
 

54hawken

Registered
I found an old briggs & stratton repairmans manual. It showed, and said:
The shaft that comes through the engine block into the external points/condenser box and hooks to the points, has an integral shoe on the opposite end that is moved by the camgear weight. When the engine is started (low rpms) the weight is held in by a spring. As the rpm are increased the centrifical force overcomes the spring and moves the weight outward, pushing the shoe, which rotates the shaft slightly to advance the timing. when rpms decrease the spring retracts the weight to retard timing. This feature makes for easy starting for a 9hp. No kickbacks & sprained fingers. Also no backfiring thru carb when accelerating.

---------- Post added at 10:39 PM ---------- Previous post was at 10:36 PM ----------

I neglected to say my above 2 posts are for Briggs model 23 with Magnematic ignition system

---------- Post added at 10:45 PM ---------- Previous post was at 10:39 PM ----------

I found an old briggs & stratton repairmans manual. It showed,
The shaft that comes through the engine block into the external points/condenser box and hooks to the points, has an integral shoe on the opposite end that is moved by the camgear weight. When the engine is started (low rpms) the weight is held in by a spring. As the rpm are increased the centrifical force overcomes the spring and moves the weight outward, pushing the shoe, which rotates the shaft slightly to advance the timing. when rpms decrease the spring retracts the weight to retard timing. This feature makes for easy starting for a 9hp. No kickbacks & sprained fingers. Also no backfiring thru carb when accelerating.

---------- Post added at 10:39 PM ---------- Previous post was at 10:36 PM ----------

I neglected to say my above 2 posts are for Briggs model 23 with Magnematic ignition system
sorry for edit
 
Top